Network services enable users to interact with various objects. For example, a social networking system allows users to designate other users or entities as connections (or otherwise connect to, or form relationships with, other users or entities), contribute and interact with their connections, post media or commentary, use applications, join groups, list and confirm attendance at events, invite connections, and perform other tasks that facilitate social interaction. External applications also use the services of a social networking system to allow authenticated users to incorporate some of the above social interactions with use of the external applications. Similar interactions are a part of the user experience within other network services.
Within these interactions, users create positive and negative feedback with regard to objects represented with the social networking system. For example, a user may take an action indicate that she liked a particular book (i.e., positive feedback). Additionally, the user may decline a recommendation within the network service that she may be interested in another book (i.e., negative feedback).